Chemistry has been explored to create liposomes and small unilamellar vesicles (SUVs). For example, Vogel et al., “DNA Controlled Assembly of Lipid Membranes,” U.S. Patent Publication No. 2010/0144848, discloses that DNA modified with two lipophilic anchors can form liposomes or SUVs. This post modification technique does not favor high surface density modification.
Hook et el., “Oligonucleotides Related to Lipid Membrane Attachment,” U.S. Patent Publication No. 2013/0252852 describes liposomes or SUVs created having an oligonucleotide having a first strand and a second strand of nucleic acid and two or more hydrophobic anchoring moieties located in its terminal ends, wherein the hydrophobic anchoring moieties are found in the bilayer. Since two cholesterol molecules are used to anchor a molecule into the lipid bilayer, this post modification technique does not favor high surface density modification.
Lu et al., “Amphiphilic Substances and Functionalized Lipid Vesicles Including the Same,” U.S. Patent Publication No. 2010/0166842 describes liposomes or SUVs comprising at least two nucleotide segments hybridized with each other. This non-post modification technique based vesicle is less efficient in stabilizing vesicles since it incorporates stabilizing moieties on both sides of the lipid bilayer.
Non-patent literature also reveals chemistry to create liposomes and SUVs, but each of these chemistries has its issues too. For example, “Liposome-Anchored Vascular Endothelial Growth Factor Aptamers” Bioconjugate Chem., 1998, 9, 573-582, describes the synthesis of aptamer DNA-functionalized liposomes and their application toward selective cancer cell targeting. The liposomes created by this method averaged 80 nanometers in size, had aptamer DNA molecules on both sides of the bilipid layer, and did not demonstrate gene regulation.
“Reversible Cell-Specific Drug Delivery with Aptamer-Functionalized Liposomes” Angew. Chem. Int. Ed. 2009, 48, 6494-6498, describes the synthesis of aptamer DNA -functionalized liposomes and their application toward selective cancer cell targeting and drug delivery. The liposomes created by this method averaged between 140 nanometers and 200 nanometers, utilize a cholesterol unit to anchor DNA into the lipid bilayer, comprise apatamer DNA molecules on both sides of the bilipid layer, and did not exhibit gene regulation.
“Selective delivery of an anticancer drug with aptamer-functionalized liposomes to breast cancer cells in vitro and in vivo” J. Mater. Chem. B, 2013, 1, 5288, discloses the synthesis of aptamer DNA-functionalized liposomes and their application toward selective cancer cell targeting and drug delivery. This work is an extension of the research disclosed in “Reversible Cell-Specific Drug Delivery with Aptamer-Functionalized Liposomes” above Like before, these particles utilize a cholesterol unit to anchor DNA into the lipid bilayer, comprise aptamer DNA molecules on both sides of the bilipid layer, and did not exhibit gene regulation.
The research in “Phospholipid Membranes Decorated by Cholesterol-Based Oligonucleotides as Soft Hybrid Nanostructures” J. Phys. Chem. B, 2008, 112, 10942-10952, characterizes cholesterol DNA-functionalized liposomes. In this report, liposomes of 33 to 35 nm in size were prepared from 1-Palmitoyl-2-oleoylphosphatidylcholine (POPC) lipid and post functionalized with cholesterol modified DNA molecule. This report does not demonstrate gene regulation, and these particles utilize a cholesterol unit to anchor DNA into the lipid bilayer.
“Bivalent Cholesterol-Based Coupling of Oligonucleotides to Lipid Membrane Assemblies” J. Am. Chem. Soc. 2004, 126, 10224-10225, describes the development of partially duplexed DNA strand containing two cholesterol units for anchoring into the lipid bilayer. The use of two cholesterol units to anchor a DNA strand into the lipid bilayer results in decreased surface density of oligonucleotides associated with the liposome.
In “Quantification of Oligonucleotide Modifications of Small Unilamellar Lipid Vesicles” Anal. Chem. 2006, 78, 7493-7498, the researchers describe the development of a technique for the quantification of DNA strands on a functionalized liposomal nanoparticle. The particle described comprises a partially duplexed DNA strand containing two cholesterol units for anchoring into the lipid bilayer. The use of two cholesterol units to anchor a DNA strand into the lipid bilayer results in decreased surface density of oligonucleotides associated with the liposome.
“Single-Molecule Detection and Mismatch Discrimination of Unlabeled DNA Targets” Nano Lett. 2008, 8, 183-188, discloses100 nanometer sized liposomes functionalized with partially duplexed DNA strand containing two cholesterol units. This work is an extension of the research disclosed in “Bivalent Cholesterol-Based Coupling of Oligonucleotides to Lipid Membrane Assemblies” and “Quantification of Oligonucleotide Modifications of Small Unilamellar Lipid Vesicles” above. Like before, these particles comprise a partially duplexed DNA strand containing two cholesterol units for anchoring into the lipid bilayer. The use of the two cholesterol units to anchor a DNA strand into the lipid bilayer results in decreased surface density of oligonucleotides associated with the liposome.
“DNA-Induced Programmable Fusion of Phospholipid Vesicles” J. Am. Chem. Soc. 2007, 129, 9584-9585, is an analytical paper on the fusion of cholesterol DNA-functionalized liposomal nanoparticles. The vesicles utilized in this paper were at least 100 nanometers in size.
“Determinants for Membrane Fusion Induced by Cholesterol-Modified DNA Zippers” J. Phys. Chem. B, 2008, 112, 8264-8274, is an analytical paper on fusion of cholesterol DNA -functionalized liposomal nanoparticle, and is a continuation of the work from “DNA-Induced Programmable Fusion of Phospholipid Vesicles” described above. This paper combines sequence specific fusion with the utilization of a partially duplexed DNA strand containing two cholesterol units to anchor the oligonucleotide into the lipid bilayer (e.g., the partially duplexed DNA strand found in “Quantification of Oligonucleotide Modifications of Small Unilamellar Lipid Vesicles” above).
“Liposome-Based Chemical barcodes for Single Molecule DNA Detection Using Imaging Mass Spectrometry” Nano Lett., 2010, 10, 732-737, is an analytical paper on detection of specific DNA targets depending on the DNA sequence. This is an extension of the work from the same group that reported “DNA-Induced Programmable Fusion of Phospholipid Vesicles” that combines sequence specific fusion with different DNA anchoring (using bischolesteryl anchor, see: Anal. Chem. 2006, 78, 7493-7498).
“Programmable Assembly of DNA-Functionalized Liposomes by DNA” is an analytical paper that discloses the assembly of cholesterol DNA functionalized liposomes. In this report, liposomes with a hydrodynamic diameter of 114 and 251 nm were synthesized and post synthetically functionalized with cholesterol modified DNA molecules. The particles in this report utilize cholesterol anchoring of the oligonucleotide molecule into the lipid bilayer.